Alkaloids and antitumor antibiotics that contain piperidine and pyridine derivatives are prevalent in nature and many of these compounds display high biological activity. 2-Azabutadienes have found limited use in the synthesis of these nitrogen heterocycles due to the lack of general procedures for their preparation. This proposal outlines a novel approach for the in situ generation of cationic 2-azabutadienes from the corresponding alpha-haloaziridine, and their subsequent [4+2] cycloaddition. A comparison to known methodologies as well as various model systems will be described. Application of the methodology toward the synthesis of (+/-) kopsinine is also outlined herein.